Installation Guide for Total Systems "Gemini Ultra" into a Mac 512

[chrisrueckert]

I'm looking for the installation guide for this accelerator. The connection to the CPU of the Mac is my main concern.

 

[Phipli]

I'm looking for the installation guide for this accelerator. The connection to the CPU of the Mac is my main concern.



View attachment 67706

An absolutely lovely board. Is this the one I saw for sale in Japan a few weeks back?

Have you got a photo of the other side?

You should also have an aux power connector, possibly with an entire aux power supply.

 

[Phipli]

This thread might be useful. If you have more driver versions, please add them!

GemStart Drivers Various Versions

I swear I'd already uploaded them here somewhere but can't find them. Find attached two versions of the GemStart drivers for Total Systems 020 / 030 processor upgrades, such as the Mercury, Gemini, Gemini Ultra and Gemini Integra. Version 2.1 is good for System 6 etc, version 3 is good for...

68kmla.org

 

[zefrenchtoon]

An absolutely lovely board. Is this the one I saw for sale in Japan a few weeks back?

I was lurking at it … but too expensive for my wallet at that period of the year

 

[Phipli]

I was lurking at it … but too expensive for my wallet at that period of the year

It's ok, how could you possibly need more than 8MHz

 

[chrisrueckert]

An absolutely lovely board. Is this the one I saw for sale in Japan a few weeks back?

Have you got a photo of the other side?

You should also have an aux power connector, possibly with an entire aux power supply.

Yes, it's the one from Japan. Here's a photo of the backside.


No auxiliary PSU came with it, unfortunately.

 

[Bolle]

Originally those would have come with a clip that goes over the CPU on the logicboard and exposes pin headers for the accelerator to install onto.
Finding one of those clips is going to be next to impossible.
The most viable option is to get machined pin header strips and solder those to the CPU on the logicboard. That’s how I install CPU upgrades on my Mac Plus machines.

You also definitely want to use an auxiliary power supply. Any cheap 5V power supply will do. The original power supply came with clips to attach to the mains voltage on the analogboard so that the auxiliary PSU will turn on and off together with the machine. I tend to solder aux PSU onto the power switch instead of using clips.
For mounting the PSU you’ll have to get creative.

 

[Phipli]

No auxiliary PSU came with it, unfortunately.

That's OK, it can be worked out and a small modern PSU used.

I believe it is the brown connector. You just need to work out the pinout.

There is someone on YouTube with a similar card (slightly older model), perhaps you can ask them for their help? Here is their video

Otherwise, I can beep out how my similar card is wired. But let's see if the youtube person has the pinout first

Then the clip for the CPU looks to be missing but...

@Bolle beat me too it

 

[JC8080]

This is what I have on my plus board. This is a one-piece pin header with supports connecting the sides, if I do this again I will just use machined header strips like Bolle mentioned above. This is the general idea though. I don't think there is any way to avoid soldering headers to the CPU at this point. I had a board with a clip that clamped over the CPU, after sitting for years, when I tried to remove the accelerator the plastic clip just came apart. I don't believe there are any replacements available at this point.